1. Field of the Invention
This invention relates to solar stills, and more particularly, to solar stills which can be constructed inexpensively from materials which can be easily transported to the site of the still. This invention has particular utility in dry, sandy regions such as deserts, where construction materials are not readily available and costs of transporting such materials for long distances can become very high. In such regions, the only water naturally available is often either salty or brackish and an inexpensive manner of rendering such water potable is highly desirable. The distillation of the sea water can also be accomplished using this solar still.
2. Description of the Prior Art
The art of producing drinking water from salt water by means of solar distillation is well known, particularly in arid, coastal regions. Many designs of solar stills are known which use conventional construction materials, such as wood, metal, concrete, glass, etc. Typically, a material transparent to solar radiation is supported over a pool of the salt or brackish water in such a manner as to allow the radiant energy to heat and vaporize the water. The vapor thus produced then condenses as the condensate coalesces into a body of potable water. Examples of prior art are to be found in U.S. Pat. Nos. 2,813,063; 3,006,818; 3,336,206; 3,653,150; and 3,191,784.
Since the solar energy used to provide the heat of vaporization of the unpotable water is free, the economy and productivity of a solar still is tied primarily to cost of construction and of material. A common disadvantage of most prior art solar stills has been the necessary importation of bulky and costly structural elements for supporting portions of the solar still.
An additional disadvantage has been the non-utilization of natural materials such as sand or earth found at the site of construction of such a still. Use of such local materials greatly reduces the overall construction cost.